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Glossary
Apendix AApendix A
Glossary
Term Definition
ASTM American Society of Testing and Materials. Publishes many test method documents.
Brittle A failure mode. Specimen generally does not deflect far before cracking begins.
Charpy Notched or un-notched simple beam test method. Also called three-point bend.
Components End use or finished product to be tested.
Crosshead
Falling weight assembly (weights, structural members, etc.) attached to Tup. Also referred
to as “hammer” in setup menu or when discussing a pendulum.
Deflection Elastic and plastic deformation of a test specimen during an impact event.
Detector block
Precision device containing infrared light beam. Passing flag breaks beam and allows for
measurement of velocity.
Ductile A failure mode. Specimen absorbs a large amount of energy with large deflection. In a
plastics puncture test, the specimen shows only plastic flow at penetration point.
Failure mode The way in which a specimen fails during an impact event.
Flag Precision device used to interrupt infrared light beam for velocity measurements.
Fracture toughness Resistance of a material to propagation of an initiated crack under impact conditions.
Impact A situation in which a moving body strikes another body either at rest or moving.
Impact energy Total potential and kinetic energy of crosshead at impact.
Impact velocity Rate of speed of the falling crosshead at point of impact.
Incipient damage During the impact event, the point at which the specimen first experiences any damage.
Also referred to as: “onset of damage”, “first crack”, “fracture initiation point”.
IZOD Notched or un-notched cantilever beam test method.
Multi-axial test Term given to puncture testing due to the multi-axial stress state of the specimen.
NTA Normalize To Area . Energy absorption as a function of specimen cross-section.
NTT Normalize To Thickness. Energy absorption as a function of specimen thickness.
Rebound test A test in which the tup bounces off of the specimen and is arrested prior to second hit.Also
called “single impact rebound test”. Often used to find incipient damage point.
Specimen An item to be tested. Usually manufactured in accordance with a test method.
Theoretical velocity Velocity of a free falling body due to the force of gravity (does not take into effect
mechanical friction and wind resistance).
Tup Force transducer or load cell with striking tip.
Velocity slowdown Decrease in crosshead velocity from impact to the point of maximum load.
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